"10 years after their official retirement the 'Black Jet' continues to fly. And no one seems to know what’s the purpose of their secretive missions. Here’s everything we know about their flights."

"In the last few years we [Aviationist] have documented the flights of some F-117 Nighthawk Stealth Jets over Nevada, missions that have continued to be carried out well after the aircraft was officially retired from active service in 2008."

"Two retired F-117 Nighthawk aircraft have been spotted flying over Nevada airspace, and the lack of a clear explanation for their flights has sparked curiosity among US aircraft observers."

With instantaneous and intuitive 100 % metaphysical certitude [courtesy the late John McLaughlin] I can reasonably surmise these surviving and operational F-117 being used to test the various sensors of the F-35 Lightning.

IF THE LIGHTNING CAN DETECT A NIGHTHAWK IT CAN DETECT ANY OTHER WARPLANE, STEALTH OR OTHERWISE!